# ============================================
# UDC Application Update Script (PowerShell)
# ============================================

param(
    [string]$Version
)

# Set error action preference
$ErrorActionPreference = "Stop"

# Set variables
$UDC_PATH = "C:\Program Files\UDC"
$VERSION_FILE = "S:\SPC\UDC\UDC_Update.txt"
$LOG_DIR = "S:\DT\Cameron\UDC\logs"

# Get hostname and timestamp
$HOSTNAME = $env:COMPUTERNAME
$TIMESTAMP = Get-Date -Format "yyyyMMdd_HHmmss"
$LOG_FILE = "$LOG_DIR\logs_$($HOSTNAME)_$TIMESTAMP.txt"

# Flag to track if we should skip the update
$SKIP_UPDATE = $false

# Function to write logs
function Write-Log {
    param([string]$Message)
    $LogMessage = "[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] $Message"
    Write-Host $Message
    Add-Content -Path $LOG_FILE -Value $LogMessage -ErrorAction SilentlyContinue
}

# Create log directory if needed
try {
    if (-not (Test-Path $LOG_DIR)) {
        New-Item -Path $LOG_DIR -ItemType Directory -Force | Out-Null
    }
} catch {
    Write-Host "WARNING: Cannot access log directory $LOG_DIR"
    Write-Host "Update will continue but logging is disabled."
}

Write-Log "============================================"
Write-Log "UDC Update Script Started on $HOSTNAME"
Write-Log "============================================"

# ============================================
# Step 1: Check if PPMon.exe or ppdcs.exe are running
# ============================================
Write-Host "Checking for conflicting processes..."
$conflictingProcesses = Get-Process -Name "PPMon", "ppdcs" -ErrorAction SilentlyContinue

if ($conflictingProcesses) {
    foreach ($proc in $conflictingProcesses) {
        Write-Log "$($proc.Name).exe is running. Skipping update process."
        Write-Host "$($proc.Name).exe is running. Update will be skipped."
    }
    $SKIP_UPDATE = $true
}

# ============================================
# Step 2: Check if UDC directory exists
# ============================================
Write-Host "Checking if UDC is installed..."
if (-not (Test-Path $UDC_PATH)) {
    Write-Log "UDC directory not found. Exiting."
    Write-Host "UDC is not installed on this machine."
    exit 0
}

# ============================================
# Step 3: Check if UDC.exe exists
# ============================================
$UDC_EXE = "$UDC_PATH\UDC.exe"
if (-not (Test-Path $UDC_EXE)) {
    Write-Log "UDC.exe not found. Exiting."
    Write-Host "UDC.exe not found in installation directory."
    exit 0
}

# ============================================
# ONLY PROCEED WITH UPDATE IF NOT SKIPPED
# ============================================
if (-not $SKIP_UPDATE) {
    
    # ============================================
    # Step 4: Determine target version
    # ============================================
    if ($Version) {
        $NETWORK_VERSION = $Version
        Write-Host "Using override version: $NETWORK_VERSION"
        Write-Log "Override version specified: $NETWORK_VERSION"
    } else {
        if (-not (Test-Path $VERSION_FILE)) {
            Write-Log "Version file not found: $VERSION_FILE"
            Write-Host "ERROR: Version file not found."
            exit 1
        }

        Write-Host "Reading version information..."
        try {
            $versionContent = Get-Content $VERSION_FILE | Where-Object { $_ -match "Version:" }
            $NETWORK_VERSION = ($versionContent -split ":")[1].Trim()

            if ([string]::IsNullOrEmpty($NETWORK_VERSION)) {
                throw "Could not parse network version"
            }

            Write-Host "Network version: $NETWORK_VERSION"
            Write-Log "Network version: $NETWORK_VERSION"
        } catch {
            Write-Log "Could not read network version. Error: $_"
            Write-Host "ERROR: Could not determine network version."
            exit 1
        }
    }

    # Build source path from version
    $SOURCE_PATH = "S:\SPC\UDC\UDC_$NETWORK_VERSION"

    # ============================================
    # Step 5: Check if source files exist
    # ============================================
    if (-not (Test-Path $SOURCE_PATH)) {
        Write-Log "Source path not found: $SOURCE_PATH"
        Write-Host "ERROR: Update source files not found at $SOURCE_PATH"
        exit 1
    }

    # ============================================
    # Step 6: Get local UDC.exe version
    # ============================================
    try {
        $fileVersion = (Get-Item $UDC_EXE).VersionInfo.FileVersion
        # Trim to 3 parts if it has 4 (e.g., 1.0.30.0 -> 1.0.30)
        $versionParts = $fileVersion.Split('.')
        if ($versionParts.Count -eq 4) {
            $LOCAL_VERSION = "$($versionParts[0]).$($versionParts[1]).$($versionParts[2])"
        } else {
            $LOCAL_VERSION = $fileVersion
        }
        
        Write-Host "Local version: $LOCAL_VERSION"
        Write-Log "Local version: $LOCAL_VERSION"
    } catch {
        Write-Log "Could not read local version. Error: $_"
        Write-Host "ERROR: Could not determine local version."
        exit 1
    }

    # ============================================
    # Step 7: Compare versions
    # ============================================
    try {
        $netVer = [version]$NETWORK_VERSION
        $localVer = [version]$LOCAL_VERSION
        
        if ($netVer -eq $localVer) {
            Write-Log "Versions match ($LOCAL_VERSION). No update needed."
            Write-Host "Version is current. No update required."
            $SKIP_UPDATE = $true
        }
        elseif ($netVer -le $localVer) {
            Write-Log "Network version ($NETWORK_VERSION) not newer than local ($LOCAL_VERSION)."
            Write-Host "Local version is current or newer. No update required."
            $SKIP_UPDATE = $true
        }
        else {
            Write-Host "Update required: $LOCAL_VERSION -> $NETWORK_VERSION"
            Write-Log "Update required: $LOCAL_VERSION -> $NETWORK_VERSION"
        }
    } catch {
        Write-Log "Error comparing versions. Error: $_"
        Write-Host "ERROR: Could not compare versions."
        exit 1
    }

    # ============================================
    # Step 8: Perform update if needed
    # ============================================
    if (-not $SKIP_UPDATE) {
        
        # Kill UDC.exe if running
        Write-Host "Checking if UDC.exe is running..."
        $udcProcess = Get-Process -Name "UDC" -ErrorAction SilentlyContinue

        if ($udcProcess) {
            Write-Host "UDC.exe is running. Stopping process..."
            Write-Log "Killing UDC.exe"
            try {
                Stop-Process -Name "UDC" -Force
                Start-Sleep -Seconds 2
                Write-Log "UDC.exe stopped successfully"
            } catch {
                Write-Log "Warning: Could not stop UDC.exe. Error: $_"
                Write-Host "WARNING: Could not stop UDC.exe"
            }
        }

        # Copy update files
        Write-Host "Copying update files..."
        Write-Log "Copying files from $SOURCE_PATH to $UDC_PATH"

        try {
            # Use robocopy for better performance and logging
            $robocopyArgs = @(
                $SOURCE_PATH,
                $UDC_PATH,
                "/E",      # Copy subdirectories including empty ones
                "/NFL",    # No file list
                "/NDL",    # No directory list
                "/NJH",    # No job header
                "/NJS",    # No job summary
                "/NC",     # No class
                "/NS",     # No size
                "/NP"      # No progress
            )
            
            $result = robocopy @robocopyArgs
            
            # Robocopy exit codes: 0-7 are success, 8+ are errors
            if ($LASTEXITCODE -ge 8) {
                throw "Robocopy failed with exit code $LASTEXITCODE"
            }
            
            Write-Host "Files copied successfully."
            Write-Log "Files copied successfully."
        } catch {
            Write-Log "ERROR: File copy failed. Error: $_"
            Write-Host "ERROR: Failed to copy update files."
            exit 1
        }
    }
}

# ============================================
# Step 9: Ensure UDC.exe is running (ONLY if no conflicting processes)
# ============================================
# Re-check for conflicting processes before starting UDC
$conflictingProcesses = Get-Process -Name "PPMon", "ppdcs" -ErrorAction SilentlyContinue

if ($conflictingProcesses) {
    Write-Log "Conflicting processes still running. Will not start UDC.exe"
    Write-Host "Conflicting processes detected. UDC.exe will not be started."
} else {
    Write-Host "Verifying UDC.exe is running..."
    $udcProcess = Get-Process -Name "UDC" -ErrorAction SilentlyContinue

    if (-not $udcProcess) {
        Write-Host "UDC.exe is not running. Starting it now..."
        Write-Log "UDC.exe not running. Starting UDC.exe"
        
        try {
            Start-Process -FilePath $UDC_EXE
            Start-Sleep -Seconds 2
            
            # Verify it started
            $udcProcess = Get-Process -Name "UDC" -ErrorAction SilentlyContinue
            
            if ($udcProcess) {
                Write-Log "UDC.exe started successfully."
                Write-Host "UDC.exe started successfully!"
            } else {
                Write-Log "WARNING: UDC.exe may not have started."
                Write-Host "WARNING: UDC.exe may not have started properly."
            }
        } catch {
            Write-Log "WARNING: Could not start UDC.exe. Error: $_"
            Write-Host "WARNING: Could not start UDC.exe"
        }
    } else {
        Write-Log "UDC.exe is already running."
        Write-Host "UDC.exe is already running."
    }
}

Write-Log "UDC Update Script Completed"
Write-Log "============================================"
exit 0